To make your own electric car charger waterproof, you need to buy a waterproof shell and a charger suitable for electric car batteries. Put the charger into the waterproof housing, plug in the power supply and the charging plug of the electric vehicle, make sure the connection is secure. Use waterproof tape or glue to seal the interfaces and openings on the housing to ensure that water does not seep inside.
Finally, test whether the charger works normally, and pay attention to regularly check the waterproof performance to ensure safe use.